Blasting-cap



(No Model.)

G. H. SAMPSON.

BLASTING CAP.

Patented sept. 1o, 1895.A

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SPECIFICATION forming part of Letters Patent No. 546,030, dated September 1.0, 1895.

Application tiled November 2, 1894. Serial No, 527,704. (No model.)

/b @ZZ whom it may concern.-

Be it known that I, GEORGE H. SAMPsoN, a citizen of the United States, residing at Medford, county of Middlesex, State of Massachusetts, have invented certain new and useful Improvements in Blasting-Caps, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification.

My invention relates to an exploder-cap or detonator employed in blasting operations to effect the explosion of the blasting-charges, which caps, as now generally constructed, contain a quantity of some detonating material, such as fulminate of mercury, and are furnished with a primer and firing-wires adapting it to be ignited by an electric current, and which primer is iixed in and closes the open end of the cap, or they are furnished with a blasting-fuse inserted in the open end of the cap and around which fuse said end is closed, as by crimping the cap-body to the fuse.

My invention consists, primarily, in the combination, with a main shell constituting the cap-body in a blasting-cap of the class stated, of a supplemental charge-holding shell adapted in length and diameter to seat within the said main shell,with its lower end resting upon the bottom of said-shell, said supplemental shell being in frictional engagement with said main shell to hold it toits seat therein, as hereinafter set forth.

In the drawings, Figure l is a vertical elevation, in perspective, of the main shell of a blasting-cap. Fig. 2 is a similar. View of my supplemental charge-holding shell. Fig. 3 is a vertical central sectional View of the said shells united in conformity with my invention. Fig. 4i is a similar viewr of the supplemental charge-holding shell and illustrating a modified form thereof; and Fig. 5 is'a similar view of a completed cap, showin g the same furnished with a primer and electric fuse.

A is the main shell constituting the body of the cap and usually formed of metal,such as copper, as a cylinder, the lower end of which is closed. In the shells shown in the drawings the said lower end is illustrated as hemispherical in form, but any other desired and suitable contour may be given to said end. In Fig. 5 the said shellA is shown in connection with a primer D, an electric fuse composed of the Wires E', connected by a platinum bridge c, embedded in the pri mer-charge, and a seal or plug C, which fits into the open end of the shell and through which the firingwires extend. The shells A usually have a circumferential groove aon their inward faces at or near their open end, into which the material of the seal, such as sulphur in a liquid state, is allowed to run when closing the charged caps, and which serves to lock and hold the seal and primer in place in the shell.

In carrying out my invention I provide a supplemental shell B, preferably of metal, such as copper, which is adapted in length and diameter to be seated within the shellA, and which preferably corresponds externally in contour to the shape of the interior of the lower end and bottom of the said shell Aand is desirably seated against said bottom, as shown. Itis preferable that the shellBshould be of such size and shape that it will fit sufiiciently close to the inward surface of the circumferential wall of the shell B to be held toV its seat therein by the frictional contact of its exterior surface with said inward surface of the shell A, as illustrated in Fig. 3. The supplemental shell B may be made to lit somewhat loosely within the main shell, if desired, and may then be provided with a flared lip or iiange b at its open end, adapted to circumferentially hug the inward'surface of the shell A, and thus operate to detain the shell B at its seat in the shell A. This modification of the shell Bis illustrated in Fig. 5. The func' tion of the supplemental shell B is to act as the charge-holder of the quantity of the fulminate of mercury or other detonating material with which the cap is to be charged, and the principal advantage accruing from the use of the said shell as such charge-holder is that said shell may be made of such length as to give it a capacity to contain only a determinate quantity of the detonating material, so that in charging the caps the shell B may be simply filled with the detonating material and then passed with its contents to its seat in the shell A, as hereinbefore Aset forth, thereby avoiding the necessity of dividing or otherwise measuring or separating the bulk of the detonating material into individual masses of a determinate quant-ity and introducing these masses severally and unprotectedly into IOO the bottom of the ordinary shells A. The shells B, when lled with their charge of detonating material, are furthermore capable of being given a seal, as of soft Wax or other suitable material, as indicated at t', Fig. 5, before being seated in the shells A, so as to preserve their said charge from contact With any moisture which may find entrance to the cap through an imperfect seal C at the capmouth.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In a blasting-cap, the combination With Y a main-shell constituting the body of the cap, of a supplemental, charge-holding shell adapted in length and diameter to seat Within said main shell with its lower end resting upon GEORGE I-I. SAMPSON. V-itnesses:

ARDEN S. FITCH, A. T. FALEs. 

